This research focuses on selected determinants of sexual behavior and contraceptive use for adolescent girls drawn from four racial populations: Asian Americans, Blacks, Native Americans, and Whites. Attention is concentrated on the socialization processes through which these young women develop attitudes toward heterosexual behavior and the ways in which these attitudes as well as situational opportunities to engage in heterosexual behavior produce variations in patterns of heterosexual interaction during the adolescent years. The research is guided by an analytic model of the stages of heterosexual behavior which include: 1) cross-sex friendships, 2) dating, 3) sexual foreplay, 4) coitus without contraception, and 5) coitus with contraception. Behavior within these stages, as well as the probability of transition from one stage to another, is hypothesized to result most directly from the interaction of the adolescent's attitudes and opportunities related to heterosexual conduct. Adolescent attitudes are a function of internalized norms and beliefs, which stem from norms and beliefs transmitted through socialization processes as well as from the adolescent's idiosyncratic perceptions and experiences. Opportunities to engage in heterosexual behavior are determined by the interaction of several factors, primarily constraints imposed by interpersonal relationships, temporal and locational settings, and cultural contexts. The study design incorporates longitudinal as well as cross-sectional procedures. The longitudinal component will be focused on adolescent girls 13 and 15 years of age at the beginning of the study. Interviews will be conducted annually over a three-year period with the girls, their parents, one same-sex friend, and one cross-sex friend. Cross-sectional comparisons will be amplified through the inclusion of a sample of 17-year-old girls during the first year of the study and a sample of 13-year-olds during the third year. By including parents and peers in addition to the adolescents, we will provide a "triangulated" perspective on the influences and processes through which sexual attitudes and opportunities are developed and the conditions under which patterns of heterosexual behavior are formed.